3.15. Recognizing Chemical Reactions http://www.ck12.org
FIGURE 3.25
A burning campfire can warm you up on a cold day.FIGURE 3.26
Dissolving an antacid tablet in water produces a fizzy drink.FIGURE 3.27
Adding acid to milk produces solid curds of cottage cheese.Q:Did you ever make a “volcano” by pouring vinegar over a “mountain” of baking soda? If you did, you probably
saw the mixture bubble up and foam over. Did a chemical reaction occur? How do you know?
A:Yes, a chemical reaction occurred. You know because the bubbles are evidence that a gas has been produced and
production of a gas is a sign of a chemical reaction.
Summary
- Potential signs that chemical reactions have occurred include a change in color, change in temperature,
production of a gas, and production of a solid precipitate.